In general, a nozzle member is used as a nozzle for discharging or ejecting a fluid, such as gas or liquid, from a plurality of discharge holes. In order to uniformly discharge or eject the fluid, a tolerance of a diameter dimension of a through hole constituting a fluid path of a nozzle member may be as small as possible, the through hole may be highly precisely formed, and roughness of an inner wall surface of the is through hole may be low.
The through hole of the nozzle member may be a minute hole having a small diameter dimension, and the plurality of through holes may be formed in a direction of the center axis of the nozzle member.
For example, according to Japanese Laid-Open Patent Publication No. hei 10-88416 (hereinafter, referred to as Reference Document 1), a nozzle piece including a plurality of discharge holes is installed to a nozzle body so as to increase the number of discharge holes of the nozzle body. Also, Reference Document 1 discloses a spinning nozzle to relatively reduce the number of nozzle pieces with respect to the number of discharge holes of the nozzle body.
Also, Japanese Laid-Open Patent Publication No. 2001-3221 (hereinafter, referred to as Reference Document 2) discloses a spinning nozzle (mouth piece) including a discharge hole having a diameter dimension of 0.2 mm, and an inner wall surface roughness of 1 S or lower.
The discharge hole of the spinning nozzle generally has a small diameter of about 0.2 mm, and is preferable to have an inner wall surface having a low roughness. Accordingly, the discharge hole is formed via a laser processing or precise processing, and then the inner wall surface of the discharge hole is polished.
The plurality of (tens of) discharge holes are required to be formed in the spinning nozzle. However, when the discharge holes are directly formed in a nozzle body, the spinning nozzle is considered to be defective if just one discharge hole is defective. Thus, material costs and huge resources spent on the spinning nozzle are wasted. Accordingly, in order to reduce such wasted manufacturing costs, Reference Document 1 discloses a method of manufacturing the spinning nozzle by separately manufacturing a nozzle member (the nozzle piece) including at least one discharge hole via an injection molding method, or the like, and then installing and fixing the nozzle member to an installation hole (through hole) pre-formed in the nozzle body, as disclosed in Reference Document 1.
When this method is used, the manufacturing costs are reduced when the number of discharge holes is relatively larger than the number of nozzle members, and moreover, spinning efficiency is increased as the number of discharge holes is increased. Accordingly, the number of discharge holes formed in the nozzle members may be preferably as many as possible, and the spinning nozzle is suitable for manufacturing a microfiber when the discharge holes have a small diameter dimension.
The inner wall surface of the discharge hole largely affects flow resistance of melted resin, and is related to the quality of a spun thread, and thus may have a roughness of 1 S or lower.
However, when a nozzle member including a plurality of through holes (minute holes) is manufactured by using an injection molding method or an extrusion molding method, wherein the injection molding or extrusion molding method is largely used as a simple and optimum method for forming a minute path including a discharge hole for a fluid, and a diameter of a through hole-forming pin (round rod) used in a mold is 0.2 mm (200 μm) or lower, or 0.1 mm (100 μm) or lower, the through hole-forming pin may be damaged by being bent or broken. Accordingly, the through holes may be difficult to be manufactured.
Meanwhile, as an ideal nozzle characteristic, a fluid needs to be straightly discharged in a laminar flow when the fluid is discharged from a through hole of a nozzle member, because a problem may occur when the fluid is turbulently discharged. The through hole of the nozzle member suitable for discharging the fluid in the laminar flow requires a large length-to-diameter ratio (L/D), i.e., an aspect ratio, wherein the aspect ratio may be 5 or above, in detail, 20 or above. Moreover, when the roughness of the inner wall surface of the through hole is low, the flow resistance of the fluid is small, and thus a turbulent discharge of the fluid may not occur.
However, when an injection molding method or an extrusion molding method is used to form a through hole having a diameter of 200 μm or less, in detail, 100 μm or less, and an aspect ratio of 5 or above, a through hole-forming pin used in a mold may be deformed or damaged. Also, when a laser processing method is used, it is difficult to make a diameter of the through hole identical along the overall length of the through hole, and to polish the inner wall surface of the through hole. Alternatively, when the through hole is formed by using a tool, such as a micro drill, the rigidity of the tool is decreased below a through hole-forming resistance, as the diameter of the tool is decreased. Accordingly, the tool may often be deformed or damaged, and thus it is difficult to form the through hole. Moreover, when the diameter of the through hole is 100 μm or less, it is very difficult to form the through is hole by using the tool. Also, in the injection molding method, about 20% of thermal plastic resin is mixed with ceramic powder, and thus a dense sintered body having a high relative density cannot be obtained.
As described above, a conventional nozzle member including a through hole, which has a diameter of 100 μm or lower and an aspect ratio of 5 or above, is very difficult to be manufactured, and a through hole constituting a minute hole having a diameter of 50 μm or lower and an aspect ratio of 5 or above cannot be manufactured. In other words, it is difficult to decrease the diameter of the through hole of the conventional nozzle member, and the use of a nozzle including the conventional nozzle member is limited, and thus the nozzle cannot perform various high-quality operations.
A vacuum suction plate that is generally used when manufacturing a semiconductor may generally include, aside from a suction plate for polishing, a porous material including ceramics or other hard materials, as disclosed in Japanese Laid-Open Patent Publication No. hei 6-143073 (hereinafter, referred to as Reference Document 3). However, the vacuum suction plate including the porous material is manufactured by molding raw material powder, such as ceramics, into a plate shape, and then sintering the raw material powder, and thus the porosity of the entire surface of the vacuum suction plate may not be uniform, and pore diameters on a surface contacting the semiconductor may vary. Accordingly, suction power of the vacuum suction plate may vary according to each pore diameter, and thus a very thin semiconductor may be dented due to the suction power in a portion where a pore diameter is relatively large. Also, since the strength of the porous material is low, a particle of the porous material may be worn out or damaged, thereby leaving flaws on the semiconductor.
Also, since the vacuum suction plate formed of the porous material generally has a maximum pore diameter of hundreds of micrometers, and moreover, has a very large aeration rate, when a semiconductor smaller than a diameter of a suction surface of the vacuum suction plate is suctioned and moved, vacuum suction power is used for an area other than a surface contacting a relatively small semiconductor, and thus semiconductors in different sizes cannot be uniformly suctioned. Accordingly, the vacuum suction plate of Reference Document 3 requires a sealing unit for blocking suction air by impregnating resin in a suction hole according to is various concentric rings having different dimensions.
When a nozzle member including a minute and long through hole having a diameter of 100 μm or lower and an aspect ratio of 5 or above according to the present invention is applied to the vacuum suction plate, stable suction power based on stable fluid flow is obtained, and thus the problems described above may be resolved. Also, when gas including various components is discharged, fluid resistance in the minute and long through hole is low, and thus energy may be saved by reducing the pressure for supplying the gas.